Detonator



Patented Jan. 21, 1930 FRANK H. BERGEIM, OF 'WOODBURY, JERSEY, ASSIGNORTO E. I. DU PONT DE NEMOURS & COMPANY, OF WILMINGTON, DELAWARE, ACORPORATION OF DELA- WARE .DETONATOR No Drawing.

This invention relates to the production of an improved detonator. Moreparticularly it relates to a composition blasting cap containingerythritol tetranitrate.

Blasting caps are ordinarily made by pressing a base charge into ametallic shell, and on top of this is pressed a priming charge with orwithout a capsule, depending upon the kind of primer used. Among theexplosives which have been used as base charges are trinitrotoluene,tetryl, nitrated ivory nut meal, and smokeless powder. The most commonlyused primers are mercury fulminate and lead azide.

While the above mentioned base charges have been used with a certaindegree of success, it is desirable that they should possess a greaterdegree of sensitiveness to detonation by a primer, thus insuring regularperformance, a matter of considerable importance in blasting practice. Ashot that fails in blasting is a source of danger and expense.

An object of my invention is to provide a detonator that insures moreregular performance than has hitherto been possible. Other objects willappear as the description proceeds.

I have found that desirable results can be obtained by incorporatingerythritol tetranitrate into the cap composition. The erythritoltertanitrate may be incorporated in various Ways. I may, for example,use any of the usual base charges in admixture with erythritoltetranitrate, or, if I desire a particularly powerful cap, I may useerythritol tetranitrate as the sole base charge. I have found that a capusing erythritol tetranitrate alone as a base charge is more powerfulthan any of the commercial blasting caps now used. This great strengthis of advantage in insuring transmission of the cap explosion to themain bulk of blasting explosive. It has also an economic advantage inthat it permits using smaller charges than can be used successfully withthe ordinary base charges. A further advantage obtained by usingerythritol tetranitrate as a base charge is that successful caps can bemade using mercury fulminate without a capsule as 9.

Application filed May 3, 1928. Serial No. 274,966.

primer. This effects a saving both in operation and materials.

In my U. S. Batent 1,691,954, dated Nov. 20, 1928, I have pointed outthat erythritol tetranitrate has a melting point of 61 C. This lowmelting point makes this compound well adapted to casting and I havefound that when cast this material can be detonated by means of aprimary detonating compound such as mercury fulminate and in this formconstitutes a very powerful detonating agent.

From the foregoing it will be seen that my invention is of wideapplication, and that, whereas I have confined my description of its useto blasting caps, it is understood that erythritol tetranitrate isequally well adapted to use in other detonating devices as, for example,booster charges for high explosive shells, which charges perform thesame function with respect to the main charge in the shell as does thebase charge in a blasting cap with respect to the dynamite.

The following are by way of illustration examples of blasting caps madein accordance with my invention: For a cap containing no inner capsule Imay use a pressed base charge of erythritol tetranitrate ranging from 2grains to 10 grains, depending on the strength of cap desired, with asuperimposed charge of 8 grains of a 90-10 mixture of fulminate andchlorate. For a cap containing an inner capsule, I may use a base chargeof 2 to 8 grains of erythritol tetranitrate with a top charge of 5grains of 9010 fulminate-chlorate mixture.

As many apparently widely different embodiments of this invention may bemade without departing from the spirit thereof, it is to be understoodthat I do not intend to limit myself to the specific embodiments thereofexcept as indicated in the appended claims.

I claim:

1. A detonator having a main charge comprising erythritol tetranitrate.

2. A detonator compnising erythritol tetranitrate and a primarydetonating compound.

3. A blasting cap having a main charge comprising erythritoltetranitrate and a primer comprising fulminate of mercury.

4. A detonator having a main charge comprising cast erythritoltetranitrate.

5 5. A detonator comprising a base charge of cast erythritoltetranltrate and a top charge of a primary detonating compound. I 6. Ablasting cap comprising a base charge of cast erythritol tetranitrateanda, priming 1Q charge of fulminate of mercury. p

In testimony whereof, I aflix my signature.

FRANK H. BERGEIM.

